1. Field of the Invention
The present invention relates to an auger type ice making machine.
2. Description of the Related Art
An auger type ice making machine is structured, for example, by a driver apparatus composed of a gear motor, a coupling, a housing, and the like, an ice making cylinder disposed in an upper portion of the driver apparatus, and an evaporator disposed in the periphery of the ice making cylinder, as disclosed in Japanese Patent Application Laid-open No.4-161773 In addition, the structure has component parts, such as an auger which is driven by the driver apparatus and is disposed coaxially in the internal portion of the ice making cylinder, a pressing head (stationary blade) disposed in an upper portion of the ice making cylinder, a guide cylinder disposed in an upper portion of the compressor head, and a cutter disposed within the guide cylinder. Water for manufacturing ice is supplied to the ice making cylinder by the evaporator during ice making operation, and then the water is cooled so that a thin layer of ice forms on an internal wall surface of the ice making cylinder. Thereafter, the formed ice is scraped off by the auger, which is rotationally driven by the gear motor, while being sent upward in sequence to a compression path of the compressor. The ice is compressed when pushed up through the compression path, and made into compressed ice blocks. The compressed ice blocks are cut into an appropriate size by the cutter, and supplied continuously to the outside of the machine from the guide cylinder.
The following abnormalities may arise relating to rotation of the auger in auger type ice making machines structured as stated above. Namely, there are exemplified the following abnormalities;
(1) stoppage of auger rotation;
(2) hunting phenomenon; and
(3) reverse auger rotation.
Stoppage of auger rogation, which is caused by a drop in the voltage supply, an overload on the ice making machine, etc., may lead to a phenomenon in which the load on the gear motor becomes larger, and the gear motor finally stops moving. If stoppage of auger rotation occurs, the following problems are concerned: an excessive load on the driver apparatus such as the gear motor; no performance of heat exchange in the evaporator, whereby coolant that is vaporized by a pressure reduction valve returns to liquid coolant; and damage to the compressor due to a liquid back phenomenon in which the liquid coolant is sucked back into the compressor. In addition, if the cause of auger rotation stoppage is eliminated (for example, the electric power source voltage returns), then the hunting phenomenon may develop because the evaporator is frozen.
The hunting phenomenon develops as discussed below. Since the gear motor is used for smooth upward movement of ice, the reduction ratio is large (on the order of 1:204). In a case, for example, of a sudden constraint during operation following a stoppage in auger rotation as discussed above, then a repulsive force is applied due to an impact between an output gear and a drive gear. A large torque is generated in the reverse direction, and there is a reverse operation in backlash for the entire motor. In addition, an output shaft is again constrained, and therefore a large torque, in which a stalling torque is added to a repulsive torque, acts in the direction of normal operation. The hunting phenomenon develops by repeated generation of normal torque and reverse torque. If the hunting phenomenon develops when, for any reason, the inside of the evaporator has become frozen or the load on the gear motor is larger than the stalling torque, and then there is the chance that damage will occur to the driver apparatus, such as the gear motor.
Further, reverse auger rotation starts for cases in which a phase of an electric power source voltage connection is reversed in a three phase gear motor. At this time, ice that must be conveyed upward within the ice making cylinder is pressed down so that not only can ice no longer be manufactured, but there is also the chance of significant damage to the structural components of an ice making mechanism portion.
In order to avoid the above problems caused by abnormalities in auger rotation, the following methods are conventionally employed for detecting rotational abnormalities or conditions under an influence of rotational abnormalities. Namely, there are exemplified the following methods:
(A) a method of detecting the value of the electric current of the gear motor;
(B) a method of detection in accordance with temperature; and
(C) a method of detecting low voltage.
Specifically, the value of the electric current flowing in the gear motor increases due to an increase in the load applied to the gear motor caused by freeze or the like, and manufacturing is stopped by use of the method of detecting the electric current value to detect an increase in the electric current value. With the temperature detection method, heat exchange is not performed in the evaporator for cases in which a frozen state develops, and the evaporation temperature is abnormally reduced. The frozen state is thus detected by sensing the temperature reduction. A sensor for detecting insufficient voltage is used in the low voltage detection method. A reset voltage and a stop voltage are set, and manufacturing is stopped for cases in which the voltage supplied falls below the set values.
However, there are problems (i), (ii), and (iii), as shown below, associated with the conventional abnormality detection means discussed above.
Problem (i): Relating to the method (A), first, the value of the electric current is influenced by changes in the voltage. In particular, the voltage supplied to the gear motor also decreases for cases in which a frozen state develops that is caused by low voltage, and therefore the electric current value does not increase so that abnormality detection cannot be accurately performed. Second, control must be performed so that the starting current is canceled to avoid stoppage in manufacturing caused by error by a starting current that develops during initial startup. Third, there is a problem in that wire breakage and reverse auger rotation cannot be detected.
Problem (ii): Relating to the method (B), abnormality detection is performed by use of the temperature at the exit of the evaporator, but the temperature at the exit once drops to a set value during startup (caused by a large load during startup, or by the response characteristics of the pressure reduction valve). In order to avoid this, a protection circuit (manufacturing stop circuit) must therefore be canceled during a predetermined amount of time after startup. Further, the (B) method is one for detecting freeze, and there is a problem in that abnormality detection is not performed if the hunting phenomenon develops without freeze for cases, for example, in which a load greater than the stalling torque involves during ice making operation.
Problem (iii): Relating to the (C) method, the development of trouble caused by voltage drops can be prevented, but there is a problem in that the development of trouble due to overloads or other causes cannot be prevented.
The present invention has been made to solve the aforementioned conventional problems, and an object of the present invention is therefore to provide an auger type ice making machine capable of detecting abnormalities in auger rotation without depending upon the value of electric current or voltage to a gear motor, and without depending upon evaporation temperature.
In order to attain the above-mentioned object, an auger type icemaking machine according to a first aspect of the present invention is characterized by comprising: an ice making cylinder in which a layer of ice is formed on an internal surface of the ice making cylinder; an auger for scraping off ice from the layer of ice, the auger being disposed within the ice making cylinder so as to be capable of rotation; a motor for driving the auger; and an auger rotational abnormality detection means having a detecting portion and a detection object portion, one of which being attached to a movable portion that is interlocked with the auger rotation, and the other of which being attached to a stationary portion.
An auger type ice making machine according to a second aspect of the present invention is characterized in that, in the auger type ice making machine according to the first aspect of the invention, the auger rotational abnormality detection means has a detecting portion and a detection object portion, one of which being attached to the auger, and the other of which being attached to the inner surface of the ice making cylinder.
An auger type ice making machine according to a third aspect of the present invention is characterized in that, in the auger type ice making machine according to the second aspect of the present invention, the detecting portion and the detection object portion are formed at a height that is out of an ice making region or an ice scraping-off region, which are located between the auger and the ice making cylinder.
An auger type ice making machine according to a fourth aspect of the present invention is characterized by further comprising, in the auger type ice making machine according to the first aspect of the invention, a sealing means for preventing an outflow of water for manufacturing ice within the ice making cylinder, the sealing means being provided between the ice making cylinder and the auger; a coupling for connecting the auger and the motor with each other in a position at which the adhesion of the water for manufacturing ice is prevented by the sealing means; and a housing covering the coupling, in which the auger rotational abnormality detection means has a detecting portion and a detection object portion, one of which being attached to the coupling, and the other of which being attached to the housing.
An auger type ice making machine according to a fifth aspect of the present invention is characterized in that, in the auger type ice making machine according to the first aspect of the present invention, the auger rotational abnormality detection means has a plurality of the detecting portions or a plurality of the detection object portions.
An auger type ice making machine according to a sixth aspect of the present invention is characterized by further comprising, in the auger type ice making machine according to the first aspect of the invention, a determination means for determining a classification of abnormality, in which; the auger rotational abnormality detection means has a plurality of the detecting portions; and the determination means determines a specific classification of abnormality from a combination of detection results from each of the detecting portions.
An auger type ice making machine according to a seventh aspect of the present invention is characterized in that, in the auger type ice making machine according to the first aspect of the present invention, a concave portion is formed in the movable portion or in the stationary portion; and the detecting portion or the detection object portion is housed in the concave portion.
An auger type ice making machine according to an eighth aspect of the present invention is characterized in that, in the auger type ice making machine according to the first aspect of the present invention, a through hole is formed in the movable portion or in the stationary portion; and the detecting portion or the detection object portion is housed in the through hole.